Albert keause



(No Modem A. KRAU'SE.

TUNNELING SHIELD.

Patented Sept. 22,1885.

Miami 35. f

N. PETERS. Photo-Lithographer. Wad-lawn. D. Q

ALBERT KRAUSE, OF BUFFALO, NEXV YORK.

TUNNELlNG-SHIELD.

SPECIFICATION forming part of Letters Patent No. 326,659, datedSeptember 22, 1885.

(No model.)

To aZZ whom it may concern:

Be it known that I, ALBERT KRAUSE, of the city of Buffalo, in the countyof Erie and State of New York, have invented new and useful Improvementsin Tunneling-Shields, of Which the following is a specification.

This invention relates to an improvement in that class of tubularmetallic shields which are used in tunneling through soft earth, sand,&c., for supporting the roof of the bore or heading in front of thebrick-work or arch. These shields are usually constructed with verticalfront ends and forced into the earth by jackscrews or hydraulic pressesapplied to lugs or brackets secured to the inner side of the shield andabutting against the brick-work. The upright front or entering end ofthe shield causes the earth to fall into and conceal the lower frontportion of the shield, whereby the lower front portion of the shield isrendered inaccessible to the workmen. \Vhen obstructionssuch asbowlders, for instance-are encountered by the lower front portion of theshield,it is extremely difficult to remove them, and the shield is oftenthereby deflected out of its true course. As the earth cannot be removedfrom before the lower front portion of the shield, the latter must beforced into the earth, which operation requires consider able force, andis very destructive to the shield.

The object of my invention is the construe tion of a shield which shallavoid these diffrculties; and myinvention consists, essentially, ofamovable tubular shield constructed with an overhanging front end, whichis inclined substantially in accordance with the angle of repose of thematerial in which the shield is used, whereby the entire front end ofthe shield is rendered accessible, as will be hereinafter fullyexplained, and pointed outin the claims.

In the accompanying drawings, Figure 1 is a longitudinal sectionalelevation of my improved shield constructed for tunnels of small size.Fig. 2 is a perspective view thereof.

Fig. 3 is a longitudinal section of my improved shield constructed fortunnels of large size. Fig. 4 is a cross-section in line 00 at, Fig. 3.Fig. 5 is a longitudinal section of the front end of this shield on anenlarged scale.

Like letters of reference refer to like parts in the several figures.

A represents the body of the tubular shield, made of cylindrical, oval,or any other suitable tubular form which the cross-section of the tunnelmay require, and somewhat larger than the tunnel, as usual.

a represents the front or entering edge of the shield, which is inclinedbackwardly, in accordance with the angle of repose of the material inwhich the shield is used, so that the material cannot enter the frontend of the shield, said angle averaging from forty to fifty degrees inthe loose soils in which tunnelingshields are usually employed. In smallshields the front edge, a, may be composed of a single continuousincline, as represented in Figs. 1 and 2; but in large shields it may becomposed of two parallel inclines, a. a, one below the other, asrepresented in Fig. 8, and even a greater number of inclines may beemployed, if desired. The two inclinesacareseparated by a horizontalplatform, B, secured transversely in the front portion of the shield,and serving to stiffen the front end of the shield, and affording asupport for the workmen.

0 represents a door or gate hinged to the under side of the platform Bat the front end of the latter, and serving to close the front end ofthe shield below the platform B when it is desired to exclude quicksandor other material from the shield. The door 0 is ordinarily fastenedagainst the under side of the platform B by a turn-button, d, or othersuitable catch, as represented in Fig. 5.

D is a brace hinged to the underside of the platform B, near the rearend of the latter, and serving to secure the door G when the latter islowered, as represented in Fig. 3. In this construction one workman canwork on the platform B and another below the same.

E represents an overhanging hood or top extension formed at the rear endof the shield to protect the front portion of the brick-work, and frepresents the brackets or lugs,to which the j ackscrews F are appliedin the usual mam ner.

The shield may be provided with longitudinal and transversestiffening-pieces, as may be necessary. The front end of theshieldbeinginclined in accordance with the angle of repose of the earth, sand, orother material in which the shield is used, the material cannot enterthe shield, and the entire front edge of the shield from its crown toits bottom is accessible to the workmen, who can readily removethe earthfrom before the front edge all around the shield, thereby making roomfor the shield, so that the jack-screws or other pressing appliances areonly required to move the shield into the space so formed for itsreception, instead of being employed for pressing the shield into theearth. As the entire front edge is accessible, bowlders and otherobstructions can be readily reached, and be removed or cut off, as maybe required.

Tunneling-shields have a tendency to work upwardly, owing to the factthat the earth is compact below the front end of the shield andlooseabove the same, and this tendency is readily counteracted in myimproved shield by removing the earth from under the front end of theshield, which portion of the shield is as readily accessible as the topportion.

For the same reason, the sub-drain (repre sented at G in Fig. 3) can belaid under the front end of the shield, thereby removing the water frombefore the shield and preventing it from entering the shield, andbearingpieces, composed of longitudinal timbers or twisted bundles ofstraw, can be laid under the front end of the shield, therebyfacilitating the movement of the shield and reducing the friction andthe'consequent wear, which is very severe and destructive when workingin hard gritty material.

I claim as my invention 1. A movable tubular tunneling-shield having itsoverhanging front end inclined substantially in accordance with theangle of repose of the material in which the shield is used, therebypreventing the material from entering the shield, and rendering itsentire front edge accessible, substantially as set forth.

2. Atunneling-shield provided with inclined front edges, aa, one abovethe other, and a horizont-al platform, B, substantially as set forth.

3. The combination, with the tunnelingshield. of aplatform, B, securedin the shield, and a pivoted door,O.adapted to close the spa e below theplatform, substantially as set forth.

' 4. The combination,-with the tunnelingshield, of a platform, B, hingeddoor Qand

